Acridine‐Functionalized Covalent Organic Frameworks (COFs) as Photocatalysts for Metallaphotocatalytic C−N Cross‐Coupling

Abstract Covalent organic frameworks (COFs) are structurally tuneable, porous and crystalline polymers constructed through the covalent attachment of small organic building blocks as elementary units. Using the myriad of such building blocks, a broad spectrum of functionalities has been applied for COF syntheses for broad applications, including heterogeneous catalysis. Herein, we report the synthesis of a new family of porous and crystalline COFs using a novel acridine linker and benzene‐1,3,5‐tricarbaldehyde derivatives bearing a variable number of hydroxy groups. With the broad absorption in the visible light region, the COFs were applied as photocatalysts in metallaphotocatalytic C−N cross‐coupling. The fully β‐ketoenamine linked COF showed the highest activity, due to the increased charge separation upon irradiation. The COF showed good to excellent yields for several aryl bromides, good recyclability and even catalyzed the organic transformation in presence of green light as energy source.


S1. General Remarks
All air and moisture sensitive reactions were performed using standard Schlenk-line techniques under an atmosphere of argon. Substrates, reagents, and solvents were purchased from commercial suppliers and used without further purification. The precursors such as phloroglucinol (TCI, > 99 %), resorcinol (> 98.5 %), phenol (TCI, > 99 %), 1-chloro-3nitrobenzene (TCI, > 99 %), 4- the respective power settings. [1] One or two lamps were used, depending on the required light intensity to irradiate reaction vessels located on a stirring plate (lamp-vessel distance: 4.5 cm; stirring speed: 800 rpm, Figure S2). To avoid heating of the reaction mixture, fans were used for cooling.

S7
Experiments using red light were carried out using a Kessil H160 Tuna Flora LED in "red" mode ( Figure S3). Two sealed reaction vessels were placed between two lamps on a stirring plate (4.5 cm distance from each lamp). To avoid heating of the reaction mixture, a fan was used for cooling. All reactions were performed with maximum stirring speed.  These data are in full agreement with those previously published in the literature. [2] Scheme S 2. Synthesis of 3-(4-aminoanilino)aniline (S2) from 3-nitro-N-(4-nitrophenyl)aniline (S1).
2,6-diaminoacridine (Acr): To 1.23 g (6.1 mmol, 1.0 eq.) of 3-(4-aminoanilino)aniline (S2) were 4 mL glycerol, 235 µl (6.1 mmol, 1.0 eq.) of formic acid and 660 µl (7.9 mmol, 1.3 eq.) of 37 % aqueous HCl solution added. The reaction mixture was heated to 155 °C during 30 min, kept at this temperature for 30 min before heating it to 175 °C for another 30 min. After cooling to room temperature 2.5 mL of aqueous sulfuric acid (30 %w/v) were added and the reaction was heated to 95 °C for 10 min. Subsequently, the reaction was diluted to 25 mL with H2O and the reaction mixture was kept at 0 °C for 1 h. The precipitated acid sulfate of the compound was filtered off, washed with water (40 mL) and Et2O (60 mL). The dark red powder was boiled in 10 mL of aqueous NaOH (1 M) to precipitate the 2,6-diaminoacridine. The dark brown compound was filtered and washed with ice cold water (60 mL) and cold Et2O (10 mL These data are in full agreement with those previously published in the literature. [3] Scheme S 5. Synthesis of 2,4-dihydroxy-1,3,5-triformylcarbaldehyde (DHTA) from resorcinol. These data are in full agreement with those previously published in the literature. [4] Scheme S 6. Synthesis of 2-hydroxy-1,3,5-triformylcarbaldehyde (HTA) from phenol.           h, when the still hot reaction mixture was poured into 250 mL of H2O and stirred for 20 min.
The resulting precipitate was filtered and dried under vacuo to give the product as a yellow- These data are in full agreement with those previously published in the literature. [7] Scheme S 8. Synthesis of 2,6-diaminoanthracene from 2,6-diaminoanthrone (S3).

S29
These data are in full agreement with those previously published in the literature. [8] Tp  added. An aliquot of the reaction mixture (~300 µL) was filtered, diluted with DMSO-d6 and subjected to 1 H-NMR analysis.
S37 Table S 10. Reusability of Tp-Acr COF using two blue lamp and washing with MeOH and hexane. a